This collaborative project is an investigation of gonadal hormone influences on human sexually-dimorphic cognitive and social behavior. The aims are four-fold: (a) to delineate the neural substrate of hormonal influences on cognitive abilities, especially spatial ability; (b) to determine the specific hormone (androgen or estrogen) responsible for masculine-typical development of particular behaviors; (c) to examine behaviors which are similar to those studied in laboratory animals and found to be sensitive to the early gonadal hormone environment, or which have been suggested to be hormonally influenced but have not been adequately studied in human beings; (d) to study possible hormonally-influenced early antecedents of later cognitive and social behavior. Patients (N = 350) will be recruited from several medical centers and include three groups with different abnormalities of hormone production, sensitivity, or exposure (congenital adrenal hyperplasia, androgen insensitivity, and prenatal exposure to diethylstilbestrol). Sex- and age-matched siblings and cousins will be recruited as controls (N = 350). Subjects in two age ranges (2-6 and 12 and older) will be tested on (a) a variety of tasks related to specific cortical areas or different patterns of neurological organization, and/or (b) on behaviors shown to be sexually-dimorphic in humans, or hormonally-influenced in other mammals and poorly studied with regard to hormonal influences in human beings. Behaviors to be examined include play behavior (rough-and-tumble play and toy preferences), cognitive abilities (verbal, spatial, mathematical, and reasoning abilities), cerebral hemispheric specialization (for verbal and music processing), early childhood activities, and personality. Results from this study will provide information about hormonal influences on the development of specific behaviors that are both socially and educationally relevant. They will also provide information on the relevance of animal models for understanding human hormone-behavior relationships.